1. Field of the Invention
The present invention relates to a multi-effect absorption refrigerating machine, such as an absorption refrigerating machine, a water cooling-heating machine or a heat pump absorption refrigerating machine, which is provided with two or more generators.
2. Description of Prior Art
Disposition of a direct contact type heat exchanger provided with evaporator-absorber stages in a solution channel between a primary absorber and generators in a conventional multi-effect absorption refrigerating machine has been disclosed, for instance, in U.S. Pat. Nos. 3,389,570, 3,389,571, 3,389,572, 3,389,573, 3,389,574 and 3,396,549.
In these prior art examples, however, the whole of a dilute solution generated in a final evaporator-absorber stage is supplied to a first generator, and thus a second generator is supplied with this solution after it has been concentrated in the first generator.
Therefore, the concentration of the solution supplied to the second generator is medium (between the concentration of the solution supplied to the first generator and that of the solution coming out of the second generator).
Meanwhile, the saturation temperature of refrigerant vapor working as a heat source is increases as the concentration of the solution in the second generator and the internal pressure thereof increases. In a double-effect system, the refrigerant vapor generated in the first generator is the heat source for the second generator; therefore the saturation temperature of the refrigerant vapor in the first generator must be increased in response to the increase in the concentration of the solution in the second generator and the internal pressure thereof.
Thus, the saturation temperature of the refrigerant vapor in the first generator is inevitably high in conventional machines, and this has brought about the following problems.
(1) A heat source generating high temperature output is required. PA0 (2) Since the temperature of the solution in the first generator is high, the corrosiveness of the solution is sharply increased, thereby rapidly corroding the wall of the generator, lessening the durability thereof.